Corsair AX850 850W Power Supply Review

Closer Look:

The Corsair AX850 power supply is finished off with a coat of slightly textured satin black paint that is great for hiding finger prints and minor scratches.

The rear face of the power supply is home for the usual stuff: the IEC mains input connector, on/off switch, AX850 model number panel and an exhaust grill that occupies a large area to maximize cooling. The modular cable connector panel is on the front face along with a round holographic sticker that acknowledges Ultra Products as the patent holder for the fully modular power supply technology.

The side panels carry identical AX850 model labels bearing the black and white Corsair logo which is inverted on the opposite face.

The base of the Corsair AX850 carries a comprehensive specification label that includes a specification table, agency approval logos, and hazardous / high voltage warnings in several different languages. The cooling fan grill follows the black theme with a Corsair logo at its center.

The modular cable set is large, which is to be expected, and required two photographs to really show it off. The main cables, which include the motherboard, EPS12V/ATX12V, and PCI-E cables, are of the more traditional braided round design. The peripheral cables, which include 4-pin peripheral and SATA power, are constructed using Corsairs flat cable design to ease installation and cable management. The floppy disk drive is a rare animal these days but Corsair provide two 4-pin peripheral to FDD power connector adapters cables, should they be needed.

The construction of the power supply enclosure is slightly different from the norm in that the side panels are part of the main housing and the fan is mounted to the lid. Corsair has used the San Ace 120 (12cm) double ball bearing fan rated at 12 V/0.9 A and manufactured by Sanyo Denki. The printed circuit is very cramped but the layout is tidy. The first thing I noticed is a lack of large heavy heat sinks which is probably a reflection of its high efficiency leading to low levels of heat production. Wiring inside the Corsair AX850 has been kept to minimum to reduce voltage drops and increase efficiency.

The wiring has been dramatically reduced by mounting two DC-DC converters, one for the 3.3 V rail and another for 5 V rail, on the same printed circuit board as the modular cable connectors on the rear panel. The 12 V regulator is on the main base board and to help reduce loses a low current 12 V feed is taken to supply the 3.3 V and 5 V rails and a separate high current feed for the main 12 V rail. The capacitors are a mixture of conventional electrolytic by Nippon Chemi-Con and some solid state capacitors used mainly on the DC-DC converters.

The Corsair AX850 power supply build quality is excellent with the usual high quality packaging, good set of accessories, and comprehensive user manual. Let’s move on and have a look at the specification and features and then see how well it performs.